measuring web performance (highedweb fl edition)
DESCRIPTION
Today, a web page can be delivered to desktop computers, televisions, or handheld devices like tablets or phones. While a technique like responsive design helps ensure that our web sites look good across that spectrum of devices we may forget that we need to make sure that our web sites also perform well across that same spectrum. More and more of our users are shifting their Internet usage to these more varied platforms and connection speeds with some moving entirely to mobile Internet. In this session we’ll look at the tools that can help you understand, measure and improve the web performance of your web sites and applications. The talk will also discuss how new server-side techniques might help us optimize our front-end performance. Finally, since the best way to test is to have devices in your hand, we’ll discuss some tips for getting your hands on them cheaply. This presentation builds upon Dave’s “Optimization for Mobile” chapter in Smashing Magazine’s “The Mobile Book.” This talk was given at HighEdWeb Florida.TRANSCRIPT
MeasuringWeb PerformanceDave Olsen, @dmolsenWest Virginia UniversityHighEdWeb Floridahttp://flic.kr/p/7A8xxN
slideshare.net/dmolsenwvu
introduction about me@dmolsen
The Mobile Book
• Covers everything mobile
• Produced by Smashing Media
• Chapters by Peter-Paul Koch, Stephanie Rieger, Brad Frost, Trent Walton, me & others
• Door prize here!
http://the-mobile-book.com
What I’ll Talk About
• Quick Intro About Why We Should Care About Web Perf
• Tools for Measuring Web Performance
• Setting Up a Device Lab
WHY SHOULD WE CARE ABOUT WEB PERFORMANCE?
http://flic.kr/p/4JY1Yr
brad’s iceberg
© Brad Frost
© Brad Frost
The way in which CSS media queries have been promoted for
mobile hides tough problems and gives developers a false
promise of a simple solution for designing for small screens.
Source: Jason Grigsby on Speakerdeck
“
” - Jason Grigsby @grigs
brad’s iceberg
© Brad Frost© Brad Frost
© Brad Frost
The average weight of a web page today.
Source: HTTP Archive
Images JavaScript
Flash
HTM
LC
SSOther
77%
1.3 MB
RWD sites whose small screen design weighs the same as the large screen design.
Source: Podjarny
72%
Users expect your mobile site to load as quickly as your desktop site.
71%
Source: Gomez
Bounce Rate Conversion Rate Cart Size Page Views
200ms - - - -1.2%
500ms -4.7% -1.9% - -5.7%
1000ms -8.3% -3.5% -2.1% -9.4%
CASE STUDY: MOBILE PERFORMANCE EFFECT ON BUSINESS
Source: Web Performance Today
Mobile first means performance first.
(start thinking about performance at the design stage)
Over Downloading
Download & HideDownload & ShrinkDownload & Ignore
PRIMARY PERFORMANCE ISSUES FOR RWD
Poor Networks
High LatencyVariable Bandwidth
Packet Loss
MOBILE OPTIMIZATION FOCUS
1. Reduce requests2. Reduce asset size3. Speed-up page
render
http://flic.kr/p/4zzKee
Browser cache
The simplest way to reduce requests is to make sure the browser doesn’t need to make them. Make sure assets are bring cached on the browser.
ConcatenateJS & CSS
Combine similar files together in one or multiple larger files to reduce requests. May harm performance too.
Lazy load content
Don’t make requests until necessary. Filament Group’s AJAX Include Pattern or lazyBlock.
data: URI For small images & fonts try embedding them in your CSS file by using the data: URI.
Conditional loading
Use a resource loader like Modernizr.load to conditionally include JavaScript & CSS files.
1. REDUCE REQUESTS
FE
P
FE
FE
FE
Best request is no request. Worst request is one that
blocks the parser.
Source: Ilya Grigorik
“
” - Ilya Grigorik @ilyagrigorik
Image compression
Use a service like kraken.io to optimize images. Also use CSS sprites as appropriate.
Compress HTML & CSS
Use mod_deflate to make sure text-based assets are compressed for transfer.
Try to avoid images
When possible think about avoiding images. Implement with CSS or Canvas. Or use SVG or Progressive JPEGs.
Minification Use a minifying service to make sure text-based assets are as small as possible. If using PHP use Minify.
MicroJS or, even better,
Vanilla JS
Avoid using bulky frameworks if you’re using them for simple tasks like selectors. Try microjs.com to find libraries that may be smaller & more suitable. JavaScript also blocks the rendering of the page.
2. REDUCE ASSET SIZE
P
SS
FE
P
FE
Avoid DOM reflows &
repaints
By using JS to modify the DOM you can cause unnecessary reflows & repaints of your browser. They slow down page render time as well as burn battery.
Defer loading of
JavaScript
Use HTML5’s script defer & async attributes to delay downloading files. Can also insert script elements into the DOM using the onLoad event.
Lazy load JavaScript
Comment out JavaScript that isn’t required at page load. Uncomment & eval() when required.
Touch beats onClick
While not directly related to page render, by making sure your links use a Touch event rather than an onClick event user interactions will speed up by 300ms.
Avoid SM widgets
Try using simple links to services rather than utilizing the JavaScript widgets. They’re performance hogs.
3. SPEED-UP PAGE RENDER
FE
FE
FE
FE
FE
Testing Tools
toolbox, tools
WEB PERFORMANCE TOOLS
http://flic.kr/p/4BZsQJ
DiagnosticTools
AutomatedTools
DiagnosticTools
AutomatedTools
LEARN TO LOVE THE INSPECTOR
FOLLOW ALONG BY OPENING THE DEVELOPER TOOLS IN CHROME
SAVE YOURSELF A HEADACHE &DISABLE CACHE WHEN TESTING
EXPLAINING THE NETWORK PANEL:RESOURCE SIZE
transferred size
real size
re-order
EXPLAINING THE NETWORK PANEL:LATENCY
latency + download
latency
re-order
EXPLAINING THE NETWORK PANEL:EVENTS
domcontentloaded
onload
EXPLAINING THE NETWORK PANEL:SAVING HAR FILES FOR COMPARISON
save HAR file locally
A narrower, shorter waterfall is the goal.
http://flic.kr/p/bMdzZ2
Test the squishy.
default styles vs. min-width vs. max-width
Perform
ance
http://timkadlec.com/2013/01/setting-a-performance-budget/http://flic.kr/p/7BBs6e
A budget is a guide, not a hard & fast limit. Performance tweaks are compromises.
EXPLAINING THE TIMELINE PANEL
EXPLAINING THE PROFILES PANEL:CSS SELECTORS
EXPLAINING THE PROFILES PANEL:CSS SELECTORS
EXPLAINING THE AUDITS PANEL
PAGESPEED INSIGHTS EXTENSIONhttps://developers.google.com/speed/pagespeed/insights
REMOTE DEBUGGING
Google Analytics Site Speed
http://www.httpwatch.comIE & FIREFOX PERFORMANCE ISSUES
Google Analytics Site Speed
GOOGLE ANALYTICS’ SITE SPEED
PERFORMANCE TESTING PROXIES
MobitestWebPagetest
Google Analytics Site Speed
http://www.slideshare.net/AndyDavies/web-page-test-beyond-the-basicsWebPagetest - BEYOND THE BASICS
Google Analytics Site Speed
CUSTOMIZING WebPagetest:CAPTURING EVENTS AFTER ONLOAD
CUSTOMIZING WebPagetest:BLACKHOLES FOR REQUESTS
Google Analytics Site Speed
CUSTOMIZING WebPagetest:SCRIPTING & CUSTOM VIEWPORTS
CUSTOMIZING WebPageTest:VIDEO COMPARISON
CUSTOMIZING WebPageTest:VIDEO COMPARISON - SMALL VIEWPORT
mobile bookmarklet
THE ULTIMATE MOBILE PERFORMANCE BOOKMARKLET
charlesproxy.com
SLOWING THINGS DOWN
ThrottleCharles
USING CHARLES PROXYhttp://blog.cloudfour.com/using-charles-proxy-to-examine-ios-apps/
TEST & OPTIMIZE JAVASCRIPT WITH JSPERFhttp://jsperf.com
W3C’s NAVIGATION TIMINGhttp://www.w3.org/TR/navigation-timing/
http://www.html5rocks.com/en/tutorials/webperformance/basics/
DiagnosticTools
AutomatedTools
mod_pagespeed AUTOMATES A LOThttp://developers.google.com/speed/pagespeed/mod
add_head combine_css convert_jpeg_to_progressive convert_meta_tags extend_cache flatten_css_imports inline_css inline_import_to_link inline_javascript rewrite_css rewrite_images rewrite_javascript rewrite_style_attributes_with_url
Default Filters
CodeKit
CODEKIT: WEB PERF IN YOUR WORKFLOW
Optimize Images Combine & Minify
Features
http://incident57.com/codekit/
charlesproxy.com
EMULATING MOBILE DEVICES
EmulatorsBrowserStack
eBay MobileKarma.com Cellphone store leftoversOpen device labs
GET YOUR HANDS ON REAL DEVICES
http://flic.kr/p/7972f6
OPENDEVICELAB.COM
Base on:WiFi-capable, Analytics
Rank, OS, Screen Dimensions, & Cost
Suggested focus: iPod Touch, mid-level
Android, high-end Android, a tablet, Blackberry,
Windows Phone 7
HOW TO DECIDE WHICH TO GET
iPod Touch w/ RetinaSamsung Fascinate +Google Nexus One +
$537
Example:
ADOBE EDGE INSPECT(THE APP FORMERLY KNOWN AS ADOBE SHADOW)
RESS: AN EVOLUTION OF RESPONSIVE DESIGN
http://slidesha.re/KtByzQ
WEB PERF TWEEPS TO FOLLOW
@ilyagrigorik
@andydavies
@souders @patmeenan
@stoyanstefanov
@joshuabixby @yoavweiss@scottjehl
just a sampling
Doug GapinskiStrategistmStoner
@thedougco
SPECIAL THANKS TO...
QUESTIONS?
Dave OlsenProfessional TechnologistWest Virginia University
@dmolsen
THANKS FOR LISTENING